Wall mixer



FIG. 1 is an isometric view of a wall mixer according to our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a first side view thereof; and,

FIG. 6 is a second side view thereof.

The views not shown form no part of the claimed design. 

CLAIM The ornamental design for a wall mixer, as shown and described. 